The magnetic field dependence of the chemically induced dynamic electron polarization (CIDEP) spectra of spin-correlated radical pairs (SCRPs) was studied by time-resolved EPR at three different external magnetic fields, i.e., X band (9.2 GHz, 330 mT), S band (3.0 GHz, 100 mT), and L band (1.5 GHz, 50 mT). The CIDEP spectra were obtained by the photolysis of three systems, xanthone and 2,6-di-tert-butylphenol (2,6-DBP) in a sodium dodecyl sulfate (SDS) micelle solution, zinc tetrakis(4-sulfonatophenyl)porphyrin (ZnTPPS) and p-benzoquinone (p-BQ) in a cetyltrimethylammonium chloride (CTAC) micelle solution, and acetone in 2-propanol, at low temperatures. In the two micelle systems, the SCRP spectra scarcely depend on the external magnetic field, and the decay times do not change much on going from the X band to the L band. These observations are discussed in terms of the cage escape rate and the spin-lattice relaxation rate. The strong magnetic field dependence found for the net emissive polarization in the CIDEP spectra of the xanthone and 2,6-DBP system is ascribed to the magnetic field dependence of the triplet mechanism (TM). On the other hand, the intensity of the SCRP spectrum in the acetone system drastically decreases with decreasing the magnetic field. This observation is rationalized on the basis of the restricted motions of the SCRPs in the 2-propanol solution at low temperatures.